Low pour point fluids and blends containing same

ABSTRACT

HAVE UTILITY AS LOW TEMPERATURE LUBRICANTS AND AS POUR POINT DEPRESSANTS FOR LOW TEMPERATURE LUBRICANT BLENDS.   WHEREIN R represents hydrogen or   Compounds of the formula

United States Patent [191 Clark et al.

LOW POUR POINT FLUIDS AND BLENDS CONTAINING SAME Inventors: Frank S. Clark, St. Louis, Mo.;

Walter Fink, Ruschlikon, Switzerland Assignee: Monsanto Company, St. Louis, Mo.

Filed: June 14, 1973 Appl. No.: 370,116

Related US. Application Data Division of Ser. No. 293,662, Sept. 29, 1972, Pat. No. 3,767,691.

US. Cl 252/463, 252/496, 252/78,

260/4482 Int. Cl ClOm 3/48 Field of Search 252/463, 49.6, 78

References Cited UNITED STATES PATENTS .12/1963 Lewis 252/496 X 11/1967 Kaufman... 252/496 X 11/1970 Wright l 252/496 C 8/1973 Clark et al. 252/463 X [4 1 Dec. to, 1974 OTHER PUBLICATIONS Chem. Abstracts, Vol. 54, pg. 1,378e.

Primary Examinerl-l. Sneed Attorney, Agent, or Firm-Robert E. Wexler [57] ABSTRACT Compounds of the formula wherein R represents hydrogen or 6 Claims, N0 Drawings LOW POUR POINT FLUIDS AND BLENDS CONTAINING SAME This is a division, of application Ser. No. 293,622, filed Sept. 29, 1972, now U.S. Pat. No. 3,767,691.

BACKGROUND OF THE INVENTION This invention relates to new compounds having utility as pour point depressants and to compositions containing such compounds in admixture with polyphenyl thioethers or polyphenyl ethers-thioethers and mixtures thereof having utility as low temperature lubricants.

During the past decade, the advent of more sophisticated space technology and space vehicles derived therefrom has led to increasing demands on functional fluids, especially lubricants. In the environment of space, lubricants must function at higher and lower temperatures than ever before and it has therefore been necessary that new lubricants be found which will operate at low temperatures and to modify known low temperature fluids so that they will be effective at lower temperatures.

PRIOR ART The following known prior art is pertinent to the present invention: The compound is disclosed at Chemical Abstracts, Vol. 54, p. 1,378E. The compound has a melting point of 42, a boiling point of 370 to 380, a refractive index of 1.0387 and a density of 1.5324.

U.S. Pat. No. 3,114,759 discloses the compound para-bis-phenoxyphenyl tetramethyl disiloxane in Example 2 thereof.

SUMMARY OF THE INVENTION In accordance with the present invention, it has been found that compounds of the formula are useful as low pour point lubricants having low evaporation properties and that such compounds may be added to polyphenyl thioether lubricant compositions to depress the pour point of such compositions.

The compounds of the present invention are distinguished from the prior art in that they contain no oxygen-linked phenyl groups and the phenyl linkages, in relation to each other, are meta-oriented, rather than para-oriented. The compounds of the present invention are fluid at lower temperatures than compounds of the prior art and may be thus incorporated into polyphenyl thioether compositions to give a lower pour point to such compositions than would similar compounds shown in the prior art.

Accordingly, the objective of this invention is to provide new disiloxane compounds useful as low pour point lubricants having evaporation loss characteristics comparable to similar polyphenyl thioether lubricants and to provide new low pour point lubricant blends containing such compounds.

DESCRlPTlON OF THE PREFERRED EMBODIMENTS The compounds of the present invention are prepared as follows:

When R hydrogen, the compound of the invention is prepared by reacting phenyl magnesium chloride with excess dimethyldichlorosilane to afford phenyldimethylchlorosilane, which is then reacted with (mphenylmercaptophenyl)dimethylchlorosilane in the presence of water to afford 1-( mphenylmercaptophenyl)-3-phenyl-1,1,3,3-tetramethyldisiloxane.

When

the compound is prepared by the reaction of the Grignard reagent of m-chlorophenyl phenyl sulfide with dimethyldichlorosilane to afford (m-phenylmercaptophenyl) dimethylchlorosilane. The latter compound is then hydrolyzed by standard methods to afford 1,3- bis(m-phenylmercaptophenyl) tetramethyldisiloxane.

The term pour point is defined as that temperature at which a liquid becomes non-flowing due to high viscosity.

The lubricant base stock to which the compounds of the present invention are added in order to depress the pour point thereof, without significant evaporative loss, are mixtures of polyphenyl thioethers with polyphenyl ether/thioethers. Illustrative lubricant blends to which the pour point depressants of the present invention may be added include the following:

1. a blend comprising:

a. m-bis(phenylmercapto)benzene. (30%) b. m-3-phenoxydiphenyl sulfide (30%) c. diphenyl sulfide (10%) 2. a blend comprising:

a. m-bis(phenylmercapto)benzene (50%) c. 3,3-bis(phenylmercapto)diphenyl ether (10%) and similar blends.

In order to determine the effect of the compounds of the present invention as pour point depressants and in order to evaluate the above blends into which they are incorporated, the lubricant blends are tested in a specially designed apparatus for measuring low temperature pour points. Also, the evaporation losses of these blends are found using ASTM modified procedure D972 at 400F. and 760 mm. for 6% hours. The results of testing blends 1 and 2 are set forth in the table be- TABLE-Continued Blend Evap. Loss (7:)

Pour Point. F.

The lubricating properties of blends 1 and 2 are sub stantially equivalent, as characterized by slow speed four ball tests, to the control and other similar polyphenyl thioether lubricating fluids. It should be noted, however, that the addition of the siloxane compounds of the present invention imparts unusually significant pour point depressing properties to the lubricant fluid and, as especially regards blend 2, low evaporation loss.

Additionally, the oxidative stability of lubricant fluids containing the disiloxane compounds of the present invention is comparable to standard polyphenyl thioether lubricants.

Blend 1 contains percent 1,3-bis(mphenylmercaptophenyl)tetramethyldisiloxane and 10 percent l-(m-phenylmercaptophenyl )-3-phenyltetramethyldisiloxane as pour point depressants.

Blend 2 contains percent l,3-bis(mphenylmerecaptophenyl)tetramethyldisiloxane and 10 percent 1-( m-phenylmercaptophenyl )-3-phenyltet- .ramethyldisiloxane as pour point depressants.

A lubricant comprising 80 percent l-(mphenylme rcaptophen yl )-3-phenyltetramethyldisilox- EXAMPLE 1 Synthesis of (m-Phenylmercaptophenyl)dimethylchlorosilane A mixture of magnesium metal grams), dimethyldichlorosilane (17 g.), and tetrahydrofuran (38 ml.) is heated to 40C. under a nitrogen blanket. To this mixture is added, over seven hours, a mixture of mchlorophenyl phenyl sulfide (300 g.), dimethyldichlorosilane (576 g.), and l 10 ml. of tetrahydrofuran. After stirring at about 50C. for 14 hours and refluxing at 78C. for 1 hour, the reaction is cooled and filtered.

Unreacted halide and silane are stripped to a pot temperature of 105C. After another filtration. the filtrate is vacuum distilled. giving 137 g. (37 percent) of (mphenylmercaptophenyl )dimethylchlorosilane (b. p. 142-4/0.3

EXAMPLE 2 (m-Phenylmercaptophenyl)dimethylchlorosilane g.) and phenyldimethylchlorosilane (52.1 g.) are mixed and added to 209 ml. of water and 261 ml. of ether. This mixture is refluxed for four hours. Vacuum distillation ofthe dried organic layer affords 46.6 g. of( 1-mphenylmercaptophenyl )-3-phenyll ,l ,3,3-tetramethyldisiloxane (bp. l75/0.35).

EXAMPLE 3 Synthesis of 1,3-Bis(m-phenylmercaptophenyl)tetramethyldisiloxane (m-Phenylmercaptophenyl)dimethylchlorosilane (203.6 g.) is added to 310 ml. of water and 388 ml. of ether. After 4 hours of reflux, distillation of the dried organic layer affords g. of the tetramethyldisiloxane (b.p. 2,52/0.6).

While the invention has been described by referring to certain specific embodiments, it is not so limited since many modifications and variations are possible in the light of the above teachings. The invention may therefore be practiced otherwise than as specifically described without departing from the spirit and scope thereof.

The embodiments of this invention in which an exclusive property or priviledge is claimed are defined as follows:

l. A low pour point lubricant composition comprising a polyphenyl thioether, a polyphenyl etherthioether and mixtures thereof and at least one compound of the formula X on cna a 51 O 6* P.

CH3 CH3 wherein R represents hydrogen or 2. A low pour point lubricant composition comprising a polyphenyl ether-thioether, a polyphenyl thioether, and mixtures thereof and the compound of claim I wherein R represents hydrogen.

3. A low pour point lubricant composition comprising a polyphenyl ether-thioether, a polyphenyl thioether, and mixtures thereof and the compound of claim 1 wherein R represents 4. A low pour point lubricant composition consisting essentially of about 50 percent m-bis(phenylmercapto)benzene, about 30 percent 1,3-bis( mphenylmercaptophenl)tetramethyldisiloxane, about 10 percent 1-(m-phenylmercaptophenyl)-3-phenyltetramethyldisiloxane and about 10 percent 3,3'-bis- (phenylmercapto)diphenyl ether.

5. A low pour point lubricant composition consisting essentially of about 30 percent m-bis(phenylmercapto)benzene, about 30 percent m-3-phenoxydiphenyl sulfide, about 10 percent diphenyl sulfide, about 20 percent l,3-bis( m-phenylmercaptophenyl )tetramethyldisiloxane and about 10 percent l-( mphenyimercaptophenyl)-3-phenyltetramethyldisiioxh CH iv CH 7 21116. O 1 I 6. The method of depressing the pour point ofa lubri- S Si O T R cant composition comprising a polyphenyl etherthioether and a polyphenyl thioether which comprises 5 CH3 CH3 incorporating therein an effective depressant amount wherem R represents y g 0! of at least one compound of the formula 1: 1

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,853,776 Dated December 10, 1974 Inventor(s) Frank S. Clark et al.

It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1, line 35, "-42" should be -42c.

Column 1, line 36, "370 to 380" should be 370 to 380C.

Column 2, line 44, "0." should be b.

Column 3, headings in TABLE-Continued read:

"Blend Pour Point, F. Evap. Loss (3;)

and should be Ingredient Wt.

Column 3, line 64, "l424/0.3)

should be l42-4C./0.3)

Column 3, line 67, "1- (m-p'nenylmercaptophenyl-3-phenyl-" should be l- (m-phenylmercaptophenyl-3-phenyl- Column 4, line 7, (b.p. l75/0.35)

-"" (bop. 0

Column 4, line 16, (b.p. 252/0.6)

should be (b.p. 252C./0.6).

Column 4, line 59, "phenylmercaptophenl) should be phenylmercaptophenyl) Signed and sea led this 18th day of March 1975.

El 1 L Attest:

I C. MARSHALL DANN RUTH C. MASON Commissioner of Patents Attesting Officer and Trademarks 

1. A LOW POUR POINT LUBRICANT COMPOSITION COMPRISING A POLUPHENOL THIOETHER, A POLYPHENOL ETHER-THIOETHER ANDM MIXTURES THEREOF AND AT LEAST ONE COMPOUND OF THE FORMULA
 2. A low pour point lubricant composition comprising a polyphenyl ether-thioether, a polyphenyl thioether, and mixtures thereof and the compound of claim 1 wherein R represents hydrogen.
 3. A low pour point lubricant composition comprising a polyphenyl ether-thioether, a polyphenyl thioether, and mixtures thereof and the compound of claim 1 wherein R represents
 4. A low pour point lubricant composition consisting essentially of about 50 percent m-bis(phenylmercapto)benzene, about 30 percent 1,3-bis(m-phenylmercaptophenl)tetramethyldisiloxane, about 10 percent 1-(m-phenylmercaptophenyl)-3-phenyltetramethyldisiloxane and about 10 percent 3,3''-bis-(phenylmercapto)diphenyl ether.
 5. A low pour point lubricant composition consisting essentially of about 30 percent m-bis(phenylmercapto)benzene, about 30 percent m-3-phenoxydiphenyl sulfide, about 10 percent diphenyl sulfide, about 20 percent 1,3-bis(m-phenylmercaptophenyl)tetramethyldisiloxane and about 10 percent 1-(m-phenylmercaptophenyl)-3-phenyltetramethyldisiloxane.
 6. The method of depressing the pour point of a lubricant composition comprising a polyphenyl etherthioether and a polyphenyl thioether which comprises incorporating therein an effective depressant amount of at least one compound of the formula 